Electric impulse motor-device



Feb. 5, 1957 M. MORRISON ELECTRIC IMPULSE MOTOR-DEVICE Original FiledAug. 16, 1949 2 Sheets-Sheet l INVENTOR 7/ W Illa All t I. I

Feb. 5, 1957 M. MORRISON 2,780,764

ELECTRIC IMPULSE MOTORDEVICE Original Filed Aug. 16, 1949 V 2Sheets-Sheet 2 IM i INVENTOR ELECTRIC IMPULSE MOTOR-DEVICE MumfordMorrison, Rochester, N. Y.

Original application August 16, 1949, Serial No. 110,596, now Patent No.2,659,853, dated November 17, 1953. Divided and this application October14, 1953, Serial No. 385,97

Claims. (Cl. 318-491) The present invention relates generally toelectric current impulse motors, it relates more particularly to impulsestepping devices, and it relates more specifically to impulse counters.

This application is a division of application Serial Number 110,596,filed August 16, 1949, now Patent No. 2,659,853.

Among the objects of the invention is to provide a rotating armature,which turns exactly a predetermined number of angular degrees for eachimpulse of current fed through the motor.

A further object of the invention is to provide a transducer of electriccurrent impulses into definite measured rotary motion without the use ofintermediary mechanical devices.

A further object of the invention is to provide a stepping switchoperating mechanism which has no mechanical stepping mechanism in it.

A further object of the invention is to provide an electrical impulsecounter operating mechanism which has no ratchets nor latches in it.

Further and other objects will be pointed out and obvious to thoseskilled in the art through the course of the specification.

The generic nature of the invention resides importantly in an electricmotor structure comprising a salient pole stator and a salient polerotor having pole structure providing lesser magnetic operating fluxreluctance for rotor operating in one direction than in the other, underdirect current impulse operation.

A further nature of the invention resides in a dual magnetic path forthe flux in the rotor which is caused to alternate in effectivedirection thereby causing rotor operation in a predetermined directionfor a series of direct current impulses.

A further nature of the invention resides in having a constant rotorposition holding flux which causes the rotor to be held in any positionto which it has been rotated.

A further nature of the invention resides in forming the cooperatingpoles of the stator and rotor to cause the rotor to move in onedirection and in one direction only.

A further nature of the invention resides in having a constant magneticfield which in cooperation with the structural elements of theinvention, causes the rotor to move through a definite predeterminedangular displacement for each impulse received by the stator winding.

Referring to the drawing, Fig. 1 is an embodiment of the invention, withsome of the shaft bearings removed for clearness, Fig. 2 is a section ofFig. 1, taken through the vertical center line thereof, Fig. 3 is asecond embodiment of the invention, Fig. 4 is connection diagram, whichwhen applied to Fig. 1 constitutes a third embodiment of the invention,and Figs. 5, 6, 7 and 8 are drawings useful in teaching the art of polestructure employed in the invention.

Referring to Figs. 1 and 2, 1 is a shaft carrying a rotor 2 having amultiplicity of salient poles such as 3, with interpolar spaces such as4, the structural forms of these ice poles and spaces will be disclosedin connection with Figs. 5-8 inclusive.

Fig. 1, 5 is a stator member having poles equi-angularly spaced with thepoles of the rotor, and 6 is a stator member having poles equi-angularlyspaced with the poles of the rotor. Stator members 5 and 6 are sorelated angularly that when the poles of 5 register with the poles ofthe rotor 2, the poles of 6 register with the inter-polar spaces ofrotor 2, as shown in the figure and obviously when the poles of 6register with the poles of a rotor, the poles of 5 register with theinter-polar spaces of the rotor.

Stator member 5 forms the core of magnet coil 7, and which protrudesthrough said coil forming a magnetic pole 8. Likewise stator member 6forms the core of magnet coil 9, and protrudes through said coil forminga magnetic pole 10.

Figs. 1 and 2, 11 is a shaft which may be supported in suitable bearingswhich are omitted in the figures for clearness; 12 is an armature formagnetic poles 8 and 10; 13 is a magnetic circuit member processed intoa permanent magnet, having a surface 14 spaced closely to rotor 2 todirect the flux of magnet 13 through rotor 2, and thence through statorand rotor poles to stator members 5 and 6, and thence to magnetic poles8 and 10. Permanent magnet 13 has one end 15, closely spaced to armature12, so that the magnetic circuit of permanent magnet 13 may be completedthrough armature 12, to magnetic pole 8 or 19.

Spring 16, may be employed under tension or under compression bysuitably fixing end 17 thereof, and may be employed to hold armature 12,either against pole 8, or against pole 10, if and when desired.

Wedge 18 may be inserted into space 19, eliminating possible rotation ofarmature 12, and in such a case Fig. 1 becomes, in effect, a simplemotor with a rotor, which operates under electrical impulses Without theaid of a rocking armature.

Battery 20 supplies current to coil 9 through lead 21, when key 22 islifted to contact position, and supplies current to coil 7 through lead23, when pressed to contact position.

Fig. 2 shaft 1 may be provided with a thrust bearing 24, and anadjustment 25, to conveniently fix the length of the air-gap formedbetween the surface 14 and rotor 2.

Fig. 3, is an embodiment having a shaft 101, a rotor 102, stator membersand 106, and a single coil 109 similar to the corresponding unitarynumbered members of Fig. 1. In Fig. 3, stator member 105 is processedinto a permanent magnet and member 113 is not permanently magnetized,but merely forms a return magnetic path for magnetic flux in statormember 105, and for magnetic flux in stator member 106 when currentflows in coil 109, from battery 120, through leads 123 and 126, when key122 is pressed to contact.

The magnetic circuit of Fig. 3 is completed through bar 127, whichmagnetically bridges the lower ends of stator members 105 and 106, aswell as does it serve to bridge said stator members with centralmagnetic circuit member 113 at its lower end 115.

The magnetic flux in permanent magnetic stator member 105, flows mainlythrough bar 127, thence through member 113, thence to rotor 102, andtherefrom to member 105. The magnetic flux caused in member 106 bycurrent in coil 169, flows through bar 127, thence through member 113,thence to rotor 102, and therefrom to member 1%.

Before a detailed operation of Figs. 1, 2 and 3 can be traversed, ateaching of the structure of the poles employed in the stators androtors of the figures must be set forth.

It must be understood by those skilled in the art who undertake toembody this invention in practical devices, that when motor devices aremade in sizes usually employed in the stepping switches, impulse counterand particularly in sizes useful in automobile clocks, that the fieldsof magnetic flux is sometimes greately modified by the effect of what istermed stray or leakage flux, and the relative shapes and sizes of polefaces to cause a desired flux distribution in one size of device may notgive the same distribution if made on a different scale.

Therefore in a patent specification only general directions for formingpoles can be given, and for precise performance, empirical determinationfollowing the general directions must be followed. The general teachingof the structure of the poles is given below.

In Figs. 5, 6, 7 and 8, the poles of the stators are laid out in astraight line instead of a circular line as is common practice in textsrelating to the subject. For simplicity Only two poles of rotor areshown, and the magnetic circuit return path is shown as a strip. Thefigures show only fragmentary parts of the stators, so that the polefaces can be enlarged to a size that is clearly suited to teaching thestructure.

Referring to Fig. 5, 505 and &6 are fragmentary parts of the statormembers of Figs. 1, 2, and 3, and SM is a member which represents therotor of the previous figures, but is considered to move linearly in aneasterly direction, it has two pole faces 554) and 551. When one ofthese pole faces such as 551, registers with a stator pole face such as552, the other pole face 550, registers with an inter-polar space suchas 553. The return circuit member 513 is considered stationary and inclose relation with 502.

In shaping the faces of the poles of the stator or in shaping the facesof the poles of the rotor individually or jointly the form to make isone which produces an unbalanced pull in one direction or the other byhaving the magnetic reluctance to movement of the rotor in one directionless than the magnetic reluctance to move ment in the other direction.

Referring to Fig. 5, one side of the pole faces of 505 and 5% arerounded as shown at surfaces 514 and 515. This rounding of one side ofthe pole faces causes an unsymmetrical magnetic pull on the rotor member502; and under a normal magnetic field created in 5495, pulls member5tl2 to the east; though stray, shunted or leakage fiux in the magneticcircuit can cause member 502, to be pulled to the west. However if thepole faces have sufiicient directively unsymmetrical magnetic reluctancethe rotor will move in one direction and in that direction only.

Fig. 6 shows how directively unsymmetrical magnetic reluctance isobtained by forming the faces 650 and 651, of the rotor 602. The polesof the stator members 605 and 606, may be symmetrical as shown ormodified if desired in accordance with the teachings above.

Fig. 7, shows a further form of unsymmetrical pole faces, which may beemployed as illustrated or in combination with the other pole faceteachings given herein.

Fig. 8, shows forms of pole faces which are structurally symmetrical onboth the rotor and on the stator; the unsymmetrical magnetic reluctancebeing obtained by shading coils, 810 and 811, the operation of which iswell understood in the art.

The detailed operation of Figs. 1, 2, and 3 will now be traversed withthe understanding that any of the teachings set forth in connection withFigs. 5, 6, 7 and 8, may be applied to the structures shown in Figs. 1,2, and 3. Different methods are suited to operating the structuresdisclosed in these figures and several will be traversed, others will beobvious to those skilled in the art.

Referring to Fig. 1, with rotor 2 and armature 12 in the positionsshown, and spring end 1.7 loose, rotor 12 is held in the position shown,by flux from permanent 4 magnet 13 flowing through armature 12, tomagnetic pole 8, thence to the poles of stator member 5 which are inregistration with the poles of rotor 2, through rotor 2 back topermanent magnet 13 through surface 14 (Fig. 2) thereof.

If key 22 is lifted to contact, the current through coil 10, closes thegap 19, by magnetic attraction of armature 12, and rotor 2 rotates untilthe poles of stator member 6 are in registration with the poles of rotor2, and the constant field of permanent magnet 13 holds it in thisposition, after the current in coil 9 is discontinued on breaking thecoil circuit by allowing key 22 to assume its neutral position, shown inthe figure. If key 22 is now pressed to contact, rotor 2, and armature12, return to the positions shown in the figure. The operations may berepeated indefinitely with the result that with each alternate contactof key 22, the rotor 2, moves an angular distance equal to /z the polepitch of the stator and the rotor is held in any degree of angulardisplacement to which it is revolved.

The movement of armature 12 is useful in driving electric clocks and themovement of the rotor is useful in indicating the time elapsed, if theelectrical impulses fed to coils 7 and 9 are properly timed.

Obviously, the movement of the rotor is useful in counting the number ofimpulses that is received from any source, and the application of theinvention is not a limitation thereof.

If spring bias is applied to armature 12., by means of tension orcompression from spring 16, the operation of Fig. 1 can be accomplishedby current impulses in one of coils 7 or 9 without employing currentimpulses in both. One example will suffice to teach this embodiment.

If suflicient tension is applied to spring 16, by pulling westwardly onend 17, armature 12 will assume the position shown in the figure in theabsence of current in coil 9. If sutficient current is applied to coil9, gap 19 will close as long as there is current in the coil, butsuflicient spring tension will return to armature 12 to the positionshown in the figure, in the absence of current in coil 9. The operationis thus; an impulse of current closes air-gap 19, and turns rotor 2%polepitch, on breaking the current in coil 9, armature 12 is pulled backto its starting position, and in so doing the flux of permanent magnet13, is caused to fiow through stator member 5, which causes rotor 2 toturn an additional /2 pole-pitch forward to a position correspondingwith that shown in the figure. That is, under this condition ofoperation, for each impulse in one coil, two spacing operations areperformed by rotor 2, and it always held in the second spaced position,in the absence of coil current.

An additional method of operating the motor structure of Fig. 1, is byeliminating spring 16, and employing circuit diagram Fig. 4, in whichone of the coils '7, may be connected directly to battery 23, and theother of the coils 9 is connected simultaneously to battery 2%, througha retarding circuit such as resistor 23 and capacitor 29. Ti/iomentarycontact of key 22, causes this circuit to have a time difference betweenthe maximum flux crests in the two circuits, causing two rotor spacingsfor each current impulse.

The operation of Fig. 1 with plug inserted in gap 19, is the same aswith the plug out, except that there is no movement of armature 12, andmagnetic circuit values are adjusted to give the same operation as withthe plug out, which can be done empirically.

The operation of Fig. 3 is accomplished by the magnetized memberproviding magnetic bias in one stator member, much the same way asspring to causes normal- 1y a magnetic bias in stator member 5 ofFig. 1. That is, the magnetism of stator member 1%, holds rotor 102 inthe position shown in Fig. 3, with suificient current in coil 1W5, rotor10?. is turned /2 pole-pitch, and on breaking the current in coil 109,the magnetism of member 105 turns rotor 102 an additional /2 pole-pitch,so that for each current impulse in coil 109, two rotor spacings areobtained.

The expression polar structural means causing directionallyunsymmetrical rotor air-gap reluctance is hereby defined to mean anyembodiment of the teaching herein relating thereto and particularly theteaching in connection with Figs. 5-8 inclusive.

Also where the expression permanent magnet or a similar expression isused, electromagnets are a perfectly obvious equivalent thereof.

Several embodiments of the invention have been taught, but the nature ofthe invention as encompassed in this application is more clearly setforth in the claims hereunder.

What I claim is:

1. In a motor-device driven by electric current impulses, a salient polerotor having a predetermined circumferential pole-pitch, twostator-members surrounding said rotor, each of said stator-membersindividually having a plurality of salient poles of an effective angularspacing equal to said pole-pitch, a Winding embracing the magneticcircuit of the stator-members, said winding being connectable to asource of electric current impulses, and a rockable armature forming amagnetic yoke between said stator-members completing the magneticcircuit thereof.

2. In a motor-device driven by electric current impulses, a salient polerotor having a predetermined circumferential pole-pitch, twostator-members surrounding said rotor, each of said stator-membersindividually having a plurality of salient poles of an effective angularspacing equal to said pole-pitch, the circumferential poleface sequenceof the poles of one of said stator-members being rotated one-halfpole-pitch with reference to the pole-face sequence of the other of saidstator-members, a winding embracing the magnetic circuit of thestatormembers, said Winding being connectable to a source of electriccurrent impulses, a third stator-member disposed between the other twosaid stator-members, and a rockable armature forming a magnetic yokebetween the three said stator-members completing the magnetic circuitsthereof.

3. In a motor-device driven by electric current impulses, a salient polerotor having a predetermined circumferential pole-pitch, twostator-members surrounding said rotor, each of said stator-membersindividually having a plurality of salient poles of an effective angularspacing equal to said pole-pitch, the circumferential poleface sequenceof the poles of one of said stator-members being rotated one-halfpole-pitch with reference to the pole-face sequence of the other of saidstator-members, a winding embracing the magnetic circuit of saidstatormembers, said winding being connectable to a source of electriccurrent impulses, a permanent-magnet statormember disposed between theother two said stator-members, and a rockable armature forming amagnetic yoke between the three said stator-members completing themagnetic circuits thereof.

4. In a motor-device driven by electric current impulses, a salient polerotor having a predetermined circumferential pole-pitch, twostator-members surrounding said rotor, each of said stator-membersindividually having a plurality of salient poles of an effective angularspacing equal to said pole-pitch, the circumferential poleface sequenceof the poles of one of said stator-members being rotated one-halfpole-pitch with reference to the pole-face sequence of the other of saidstator-members, a winding embracing the magnetic circuit of thestatormembers, said winding being connectable to a source of electriccurrent impulses, a third stator-member disposed between the other twosaid stator-members, and a rockable armature forming a magnetic yokebetween the three said stator-members directing the magnetic fieldcaused in said stator-members by said winding when connected to saidsource, into one and only one of said members at a time.

5. In a motor-device driven by electric current impulses, a salient polerotor having a predetermined circumferential pole-pitch, twostator-members surrounding said rotor, each of said stator-membersindividually having a plurality of salient poles of an effective angularspacing equal to said pole-pitch, the circumferential poleface sequenceof the poles of one of said stator-members being rotated one-halfpole-pitch with reference to the pole-face sequence of the other of saidstator-members, a winding embracing the magnetic circuit of thestatormembers, said winding being connectable to a source of electriccurrent impulses, a third stator-member disposed between the other twosaid stator-members, a rockable annature forming a magnetic yoke betweenthe three said stator-members completing the magnetic circuits thereof,and an elastic means connected to said armature and to a fixed positionproviding spring bias for said armature.

References Cited in the file of this patent UNITED STATES PATENTS

